One vertex per element, one color per generator, with an edge from x to x·s.
(5,6)(7,10)(8,9)(11,12)(13,14,18,16)(15,22,25,28)(17,21,19,27)(20,24,23,26)(1,2)(3,4)(6,9)(10,12)(14,16)(20,23)(21,27)(22,28) involution — undirected(2,4)(13,15,19,26,18,25,17,24)(14,20,21,22,16,23,27,28)(2,4)(13,16,18,14)(15,23,25,20)(17,21,19,27)(22,26,28,24)(5,7,8,11)(6,10,9,12)(13,17,18,19)(14,21,16,27)(15,24,25,26)(20,22,23,28)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.